android/CloudVision/app/src/main/java/com/google/sample/cloudvision/PermissionUtils.java
/*
 * Copyright 2016 Google Inc. All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.google.sample.cloudvision;

import android.app.Activity;
import android.content.pm.PackageManager;
import android.support.v4.app.ActivityCompat;
import android.support.v4.content.ContextCompat;

import java.util.ArrayList;

public class PermissionUtils {
    public static boolean requestPermission(
            Activity activity, int requestCode, String... permissions) {
        boolean granted = true;
        ArrayList<String> permissionsNeeded = new ArrayList<>();

        for (String s : permissions) {
            int permissionCheck = ContextCompat.checkSelfPermission(activity, s);
            boolean hasPermission = (permissionCheck == PackageManager.PERMISSION_GRANTED);
            granted &= hasPermission;
            if (!hasPermission) {
                permissionsNeeded.add(s);
            }
        }

        if (granted) {
            return true;
        } else {
            ActivityCompat.requestPermissions(activity,
                    permissionsNeeded.toArray(new String[permissionsNeeded.size()]),
                    requestCode);
            return false;
        }
    }


    public static boolean permissionGranted(
            int requestCode, int permissionCode, int[] grantResults) {
        return requestCode == permissionCode && grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED;
    }
}
